Fuel pump



Ot. 9 1934. E. A. RocKyvELL FUEL PUMP Original Filed Nov. 1 6, 1929 Patented Oct. 9, 1934 I FUEL PUMP Edward A. Rockwell, chicago, 111.

Application November 16, 1929, Serial No.407,357 Renewed September 7, 1933 4 Claims. (Cl. 15S-36.3)

The purpose of this invention is to provide an and of said stem. The piston is hollow for acimproved construction and arrangement of the commodating a spring,.19, reacting between the fuel line of a motor vehicle from the main fuel piston and a stop ange, 20, formed on the pump supply tank at the rear of the vehicle to the casing, said spring operating for yieldingly re- 5 engine, having features and means for preventing sisting the retraction of the piston in the cylinder 60 the carbureter being flooded by gravity flow of for its suction stroke and reacting for giving the the fuel from the rear tank when the vehicle is piston yieldingly its forcing stroke. The inner on a steep descending grade, causing the tank arm, 13a, of the lever, 13, is forked, as seen at to be at a higher level than the carbureter, and 13b, for engaging the stem, 18, by means of stops,

,10 for obviating certain defects and disadvantages 18a, 18h, on said stern, 18, said stops being spaced G5 of constructions heretofore commonly employed apart along the stem a short distance for affordby reason of possibility of draining the fuel from ing lost motion connection between the lever and the carbureter fuel chamber by siphoning back the piston for a well understood purpose in pumpto the main tank when the engine is at rest and ing devices of this character.

the vehicle upon an ascending grade, It consists A spring, 21, is provided reacting between the 70 in the elements and features of construction lever arm, 13a; and the casing for causing the shown and described as indicated in the claims. lever to follow the cam, 14, on the idle phase of In the drawing:- the latter.

Figure 1 is a diagrammatic view for showing The pumping chamber, 22, is connected by pipe 20 the relative location on the vehicle of the fuel line, 23, with the element of the system above 75 supply tank and carbureter and the several dismentioned as comprising the fuel and sediment tinctive portions and. elements of the fuel contrap, and fuel intake and discharge passages and duit from the tank to the carbureter. controlling valves, Ashown in detail in Figure 3, Figure 2 is a vertical section of a fuel feeding which will now be described. This element is pump or impulser. mounted at a point on the vehicle relatively prox- 30 Figure 3 is a vertical section of the portion of imate to the engine and remote from the fuel the fuel line comprising a fuel and sediment trap tank, and at as high a level as support for the and the intake and discharge passages and their same vcan be conveniently provided on the vehicle, controlling valves. as for example at a relatively high point on the Figure 4 is a section at the line 4 4 on Figure 3. dash. It consists of a trap chamber, 60, having 85 Referring to the drawingz-The main fuel at the upper end thereof a casing member, 61, supply tank is shown at A, the impulser or fuel in which are formed ducts, 62 and 63, constitutpumping device mounted on the engine for pumping parts of the fuel` line which comprises also ing the fuel from the main tank to the engine valve chambers, 64 and 65, for intake and outflow carbureter being shown at B. The arbureter is controlling valves, 66 and 67, respectively, the 90 indicated at C. At D there is shown an element fuel and sediment trap chamber, 68, being intercomprising a fuel and sediment trapping champosed in the course of ow between the valve ber which is associated with the portion of the chambers, 64 and 65, and having connection by fuel line in which are located the passages and means of the duct, 69, with the pumping chamber 4o valves therein which control the flow opening of the impulser, the pipe, 23,1eading, as described, 95 for flow from the main supply tank to the carfrom said pumping chamber, being connected to bureter and seating against reverse flow. said duct, 69, as seen at 70 on Figure 3. A fuel The impulser may be any usual form of pumppipe line, 73, leads from the main fuel supply ing device. As illustrated, it comprises a `pump tank, A, to the element, D, to which said pipeline l casing, 10, arranged to be mounted on the engine is connected at the inflow passage, 62, and a pipe 100 casing indicated at 11 at an aperture in the latter line, 75, connected by the discharge passage, 63, indicated at 12, through which the pump operatof said element leads therefrom to the carbureter. ing lever, 13, may protrude for encounter of an It may be noted that the fuel passages as deengine cam indicated at 14. The pump casing scribed are arranged with respect to the fuel and comprises'a pump cylinder, 15, in which the piston, sediment trapping chamber, 68, and a filter 105 16, is fitted and mounted for reciprocation byv screen, 71, therein, in a. manner familiar in such the lever, 13, which is fulcrumed in the pump devices for trapping the fuel and sediment in the casing at 17, and connected to the operating trapping chamber below the filter screen, above stem, 18, of the piston, 16, said stem being conwhich the, passage, 63, leads to the discharge i nected'to 'the piston at the lower end of the latter valve, 67, so that the fuel is freed from sedimen- 110 tary impurities before passing the discharge valve.

At a convenient point in the fuel line antecedent to the intake controlling valve, 66, and as illustrated, most conveniently at the highest point in the pipe line, 73, and in any case antecedent to the valve, 66, there is provided a restricted air bleed aperture, 90.

Upon considering this construction it may be understood that starting with the fuel line and trap chamber empty, the reciprocation of the impulser piston actuated in one direction by the engine caml and in the Ireverse direction by the spring, 19, will operate for lifting the fuel by` suction from the main tank to the trap chamber; and that when that chamber is filled, the fuel will be forced by way of the fuel pipeline, 75, to the carbureter. The details of this action may be controlled by details of the construction not described and not specifically signiilcant for the purpose of this invention, which is concerned with means for preventing the carbureter being flooded when the vehicle is on a descending grade of such steepness as to cause the fuel tank, A, to be higher than the carbureter.

And upon considering this construction it may be understood that when the vehicle is descending a gradesuch that the line :v -a: in Figure 1 would properly indicate the horizontal, in the absence of preventive means, the fuel line being filled by the action of the impulser while the vehicle is on level road, notwithstanding by gravity the fuel would not rise in the fuel line antecedent to the valve, 66, higher than the point indicated at y, yet the passages and chambers constituting the fuel line having been already filled with liquid, the entire line would constitute a siphon connection whichwould cause the fuel to be delivered by gravity to the carbureter without limit until the tank was exhausted. This result is prevented bythe air bleed, 90, located in the fuel line atta point substantially higher than the level .at which the fuel would stand in the pipe under action of gravity alone with the vehicle on the descending grade indicated.-

It will be understood that the air bleed, 90, will be restricted relativelyA to the suction capacity of the impulser so that notwithstanding the presence of said air, the impulser will be competent to lift the fuel to the height of the trap chamber and valves.

This will not operate to prevent the construction from serving its purpose of preventing the flooding of the carbureter, because, so far as the fuel is supplied by the impulser, itis absolutely under the control of the impulser, which will only operate to the limit of the engine requirements, such being `the limit of the feeding capacity of the spring, 19.

Uponfurther consideration it may be understood that when the vehicle is halted on a steep ascending grade and the engine is not running, leakage of the valves in the fuel line will tend to cause backilow of fuel from the carbureter and from the pump; and that such backflow will be promoted and become operative, notwithstanding the fact that the flow from the pump and from the carbureter will be upward to the trapping chamber and the flow controlling valves, by reason of the fact that the entire fuel line back to the main tank being full, siphon action would occur; and it will be observed that under these circumstances the air bleed, 90, will serve for breakingthe siphon so that only the fuel in the pipe line me tank;

Upon further consideration of the structure and arrangement of the several elements of the apparatus, it will be observed that the feeding capacity of the pump when the piston makes a f ull stroke, is not designed to exceed the capacity of the trap chamber between the level of the entrance to the passage, 69, and the entrance to the passage, 63, and that by reason of the lost motion provision at the forked engagement of the lever, 13, and the lever arm, 13a, with the piston stem, 18, by means of the spaced stops, 18a and 18h, makes it impossible for any suction stroke of the piston to exceed the preceding feeding stroke which in turn will be limited by the fuel requirements of the engine; and consequently in the normal operation of the apparatus, the fuel will never be drawn into the pipe line, 23, and thence into the pumping chamber.

On the contrary, the'pumping chamber and said pipe lines, 23, will be occupied by air or gas which will act as a slightly yielding piston for transmitting the impulses of the pump piston to the liquid in the fuel line. In this connection it will be observed that the pipe, 23, may be very small and that its length is limited to the few feet of distance from the pump mounted on the engine to the vehicle dash, so that the resilient yielding of the air column in this pipe is not sufficient to prevent the air from acting effectively for transmitting the impulsesas mentioned.

I claim:

l. A fluid feed system comprisingv in combination, a low level fluid supply tank, an impulser at the lower forward part of the apparatus, a. fluid line from the supply tank to the point of delivery including an elevated portion above the point of delivery, a pair of check valves in the fluid line at the elevated portion, a depending trap chamber in the fluid line between the valves, a communi-4 cation from the impulser to the trap chamber and said feed line having a restricted air bleed aperture at the elevated portion antecedent to the valves for preventing siphoning of the fluid.

2. In the construction defined in daim 1, the

upwardly for emerging from the top of the tank to a height approximating the level of the im' .pulser intake,

thence reflexed ,u for extending downwardly substantially to the level of the intake of said fluid line, thence extending forwardly for extending upwardly to said elevated portion.

3. In the construction defined in claim 1, the capacity of the trap chamber between the levels of theport of suction from the impulser and the port of fluid discharge from saidchamber being at least equal to the stroke capacity of the impulser, whereby the drawing of liquid intothe pipe line between the trap chamber and the impulser is prevented.

4:.y A fluid feed system including a low level fluid supply tank, an impulser, a fluid feed line from the supply tank to a receiving chamber includi cation from the impulser to the trap chamber and said feed line having a restricted air bleed apertureat the elevated portion antecedent to the valves for preventing siphoning of the fluid back to the supply tank. Y

EDWARD A. nocKwELL. 

